In previous research using the movement of an overhead crib mobile as a reinforcement for infant footkicks, we found that certain changes in both footkicking and emotional behaviors. This suggested that during the course of learning, infants develop certain expectancies about how their behavior will affect the enviornment and that changes in this environment lead to concomitant affective changes in the infant. The present proposal will determine the role of these affective reactions in the infant's memory to the training task. Infants will receive three days of training in the mobile conjugate reinforcement task and will experience a change in the mobile on the third day designed to produce negative affect (crying, turning away). Separate studies will investigate (i) the persistence of this negative affect upon reexposure to the new mobile, and (ii) whether this retention interval can be extended by reactivation treatments that rexpose the infant to either the moving mobile or a stationary mobile designed to reelicit the negative affect that accompanied the change in reinforcer. These studies will help to provide a necessary linkage bvetween the cognitive and affective processes involved in infant development and will aid our understanding of how infants adjust (or fail to adjust) to new environments.